The present invention relates to an adapter assembly used during in-circuit testing of printed circuit boards. More particularly, the adapter assembly of the present invention provides an electrical connection between contacts on a test fixture to corresponding contacts on a receiver of an in-circuit testing device. The adapter assembly of the present invention makes the layout and spacing of electrical contacts on the test fixture independent of the layout of electrical contacts on the receiver.
So-called wireless test fixtures are used to provide in-circuit testing of a unit under test. Such test fixtures are wireless in the sense that they use a printed wiring board to electrically connect a unit under test to an in-circuit testing device. The wireless test fixture does not utilize and discrete wiring (wire wrapping). Instead, wireless test fixtures use a printed wiring board and electrically conductive probes. The unit under test is electrically connected to the printed wiring board of the test fixture by conductive probes, and in turn the printed wiring board of the test fixture is connected to the receiver of the in-circuit testing device by another set of conductive probes.
One problem associated with the use of conventional test equipment relates to the size of the receiver. Presently, there is a requirement that the spacing and arrangement of electrical contacts on the wireless test fixture match the spacing and arrangement of electrical contacts on the receiver. Consequently, the size of the receiver which is determined by the number and spacing between of the contacts undesirably dictates the size of the wireless test fixture. To be more precise, the size of the receiver dictates the size of a printed wiring board contained in the wireless test fixture.
The manufacture of large scale (oversize) printed wiring boards is extremely expensive, and it would be highly cost effective to reduce the size of the printed wiring board contained in the wireless test fixture whenever possible.
Accordingly, an object of the present invention is to provide an adapter assembly which makes the layout and spacing of electrical contacts of the printed wiring board of the wireless test fixture independent of the layout and spacing of electrical contacts of the receiver of the in-circuit testing device.
Briefly, the present invention relates to an adapter assembly electrically connecting a printed wiring board of a wireless test fixture with an interface of an in-circuit testing device.
According to a first embodiment, a method is disclosed for making the layout and spacing of electrical contacts on a test fixture independent of a layout and spacing of corresponding electrical contacts on a receiver of an in-circuit testing device. The test fixture is used to electrically connect a unit under test to the receiver of the in-circuit testing device to inspect the unit under test.
The receiver has a mating surface having a first surface area with plural first electrical contacts arranged in a first layout, and the test fixture has a testing surface having a second surface area smaller than the first surface area with plural second electrical contacts arranged in a second layout. The spacing between adjacent second electrical contacts is smaller than the spacing between adjacent first electrical contacts.
The method includes the steps of providing a translator board having a plurality of third electrical contacts arranged on a third surface in the first layout and a plurality of fourth electrical contacts arranged on a fourth surface in the second layout. Individual third electrical contacts are electrically connected to corresponding fourth electrical contacts by conductive traces contained within the translator board.
The translator board is placed in contact with the in-circuit testing device such that the third electrical contacts of the translator board are brought into electrical contact with corresponding ones of the first electrical contacts on the mating surface of the receiver.
Next, the test fixture is placed in contact with the translator board such that the electrical contacts on the fourth surface of the translator board are brought into electrical contact with corresponding ones of the second electrical contacts on the testing surface of the test fixture.
Importantly, the translator board makes the layout and spacing of electrical contacts on the test fixture independent of the layout and spacing of corresponding electrical contacts on the receiver, and enables the use of a test fixture whose testing surface has a smaller surface area than that of the receiver of the in-circuit testing device.